CN114051593A

CN114051593A - Near-eye display device, augmented reality glasses comprising same, and operation method thereof

Info

Publication number: CN114051593A
Application number: CN202080048090.5A
Authority: CN
Inventors: 尼古拉·维克托罗维奇·穆拉韦夫; 德米特里·叶夫根耶维奇·皮斯库诺夫; 加夫里尔·尼古拉耶维奇·沃斯特里科夫; 安德烈·尼古拉耶维奇·普季林
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2019-07-12
Filing date: 2020-06-17
Publication date: 2022-02-15
Anticipated expiration: 2040-06-17
Also published as: EP3998506A4; EP3998506A1; WO2021010603A1; US20220107501A1

Abstract

A near-eye display device, an augmented reality device including the near-eye display device, and an operation method of the near-eye display device are provided. The near-eye display device includes a first expansion waveguide having a first expansion diffraction grating and a second waveguide having a second diffraction grating, and the first expansion diffraction grating and the second diffraction grating are located on different planes.

Description

Near-eye display device, augmented reality glasses comprising same, and operation method thereof

Technical Field

The present disclosure relates to a near-eye display device, an augmented reality device including the near-eye display device, and an operation method of the near-eye display device.

Background

Wearable near-eye display devices are frequently used. Users need AR devices, VR devices, etc. with a wide field of view (FOV), light weight, low cost, small size, and high resolution. Such wearable near-eye display devices may replace televisions and smart phones.

For example, augmented reality glasses systems require the possibility of superimposing virtual images over a large area, light weight, low cost, high resolution, high contrast, etc., to achieve a wide viewing angle that enables the human eye to cover the entire area seen by the person.

When these requirements are met, the near-eye display device can provide a large area and a wide FOV, enabling the eye to see the entire image without loss. There are several ways to achieve these requirements. Some methods may provide a wide FOV, but may not provide a large area that enables the eye to see the entire image without loss. Other methods may provide a large area, enabling the eye to see the entire image without loss, but may not provide a wide FOV.

Existing systems that do not use exit pupil multiplication are equipped with input and output gratings (holographic optical elements (HOE) or Diffractive Optical Elements (DOE)). These systems operate schematically as follows. The projector forms an image at infinity forming a parallel beam of light, with an input hologram or input diffractive element located on the waveguide placed in the exit pupil of the projector. Due to diffraction by the element, parallel beams are introduced into the waveguide without destroying parallelism, and then due to total internal reflection, the beams expand in the waveguide and enter an output diffractive element (HOE/DOE).

In this case, since only one diffraction order of the light beams transmitted through the diffraction grating is used and the input and output gratings are used on only one plane, the wide field at the input becomes a narrow picture at the output. The narrow picture looks uncomfortable because only the central area of the image is clearly seen when the pupil of the eye is looking forward. The image portion located at the edge of the narrow picture represents a dark area, and when the pupil of the eye moves in the vertical direction, the central portion appears as a dark area. In other words, the user can only see a narrow strip of the image.

Disclosure of Invention

Technical problem

A near-eye display device capable of providing a wide field of view (FOV) is provided.

An augmented reality device capable of providing a wide FOV is provided.

A method of operating a near-eye display device capable of providing a wide FOV is provided.

Solution scheme

According to an aspect of the present disclosure, a near-eye display device includes: a projection system configured to display an image; a first extension waveguide comprising a first surface and a second surface opposite the first surface, wherein light from the projection system is incident on the first surface or the second surface; a first expansion diffraction grating included in the first expansion waveguide; a second waveguide on which light emitted from the first extension waveguide is incident; and a second diffraction grating included in the second waveguide, wherein the first expansion diffraction grating and the second diffraction grating are located on different planes such that 0 th order diffraction light emitted from the first expansion waveguide is incident on the second waveguide.

Light from the projection system may be incident on the first expansion waveguide, and an angle at which the light is incident on the first expansion diffraction grating may have a range of 0 to 90 degrees with respect to a normal to a surface of the first expansion waveguide.

The grating lines of the first extended diffraction grating may be arranged along the projection of light from the projection system onto the first extended diffraction grating.

An acute angle between a projection of a main beam of the projection system on the plane of the first extension waveguide and a grating line of the first extension diffraction grating may have a range of +30 degrees to-30 degrees.

The first expansion diffraction grating may be located on a first surface of the first expansion waveguide on which light from the projection system is incident.

The second surface of the first extension waveguide may have a specular coating.

Light from the projection system may be incident on the first surface and the first extended diffraction grating may be located on the second surface.

The second waveguide may include a first region on which light is incident, a second region where light does not enter the user's eye, and a third region where light enters the pupil of the eye.

The near-eye display device may be configured such that diffraction does not occur in the second region of the second waveguide.

The second diffraction grating may be configured to have a relationship of diffraction efficiency of the first region > diffraction efficiency of the third region > diffraction efficiency of the second region.

The second diffraction grating may be configured to have a relationship that diffraction efficiency of the first region > diffraction efficiency of the second region — diffraction efficiency of the third region.

The first region of the second diffraction grating may have a high diffraction efficiency, and the second region and the third region may have a gradient diffraction efficiency.

The first region of the second diffraction grating may have a high diffraction efficiency, the second region may have a lower diffraction efficiency than the first region, and the third region may have a gradient diffraction efficiency.

The first extension waveguide and the second waveguide may constitute a single piece of the waveguide in a curved shape.

Each of the first expansion waveguide and the second waveguide may be configured with one of a diffractive optical element and a hologram element.

The second diffraction grating may comprise an in-coupling diffraction grating and an out-coupling diffraction grating on a single surface.

According to an aspect of the present disclosure, an augmented reality glasses includes an element for a left eye and an element for a right eye. At least one of the element for the left eye and the element for the right eye includes: a projection system; a first expansion waveguide comprising a first surface and a second surface opposite the first surface, wherein light from the projection system is incident on the first surface; a first expansion diffraction grating included in the first expansion waveguide; a second waveguide on which light emitted from the first extension waveguide is incident; and a second diffraction grating included in the second waveguide. The first expansion diffraction grating and the second diffraction grating are located on different planes such that the 0 th order diffracted light output by the first expansion waveguide is incident on the second waveguide.

The element for the left eye may be positioned separately from the element for the right eye, and the element for the right eye may be coupled with the element for the right eye.

According to an aspect of the present disclosure, a method of operating a near-eye display device includes: causing light from the projection system to be incident on the first extended diffraction grating; forming-1 order diffraction, 0 order diffraction, and +1 order diffraction from respective diffractions of the light beam incident on the first expanded diffraction grating; outputting the 0 th order diffracted light from the first extension waveguide, and inputting the 0 th order diffracted light to the second waveguide; expanding-1 st order diffracted light and +1 st order diffracted light in the first expansion waveguide due to total internal reflection, and feeding back the expanded-1 st order diffracted light and the expanded +1 st order diffracted light to the first expansion diffraction grating, and causing the expanded-1 st order diffracted light and the expanded +1 st order diffracted light to be incident on different positions on the first expansion diffraction grating; and forming a new-1 st order diffraction, a new 0 th order diffraction, and a new +1 st order diffraction from each of the-1 st order diffracted light and the +1 st order diffracted light.

Each 0 th order diffracted light incident on the second waveguide may be transmitted through the second diffraction grating via the second waveguide, diffraction of each light ray incident on the second diffraction grating may form-1 st order diffraction, 0 th order diffraction, and +1 st order diffraction, and the +1 st order diffraction may be reflected by a surface of the second waveguide, which is opposite to an eye-facing surface of the second waveguide, and may be incident on the second diffraction grating again.

Advantageous effects of the disclosure

A near-eye display device according to an embodiment may provide a wide field of view. A near-eye display device according to an embodiment may reduce manufacturing costs by including an in-coupling diffraction grating and an out-coupling diffraction grating on a single plane.

Drawings

Fig. 1 is a view schematically showing a near-eye display device according to an embodiment.

Fig. 2 is a plan view of the near-eye display device of fig. 1.

Fig. 3 is a schematic diagram of a near-eye display device according to another embodiment.

Fig. 4 illustrates diffraction efficiency according to a length of a second diffraction grating of a near-eye display device according to an embodiment.

Fig. 5 is a schematic diagram of a near-eye display device according to another embodiment.

Fig. 6 is a schematic diagram of a near-eye display device according to another embodiment.

Fig. 7 is a schematic diagram of a near-eye display device according to another embodiment.

Fig. 8a to 8c are views schematically showing a near-eye display device according to an embodiment.

Fig. 9 and 10 are views for explaining an operation method of the near-eye display device according to the embodiment.

Fig. 11 schematically illustrates a structure of an extended diffraction grating of a near-eye display device according to an embodiment.

Fig. 12 is a view for explaining the operation of the near-eye display device according to the comparative example.

Fig. 13 is a view for explaining the operation of the near-eye display device according to the embodiment.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

A near-eye display device, an augmented reality device including the near-eye display device, and an operation method of the near-eye display device according to the embodiments will now be described.

In the drawings, like reference numerals denote like elements, and in the drawings, the size of the elements may be exaggerated for clarity and convenience of explanation. Although terms such as "first", "second", etc. may be used to describe various components, these components should not be limited to the above terms. The above terms are only used to distinguish one component from another component.

The use of the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. The terms "comprises" and/or "comprising" or "includes" when used in this specification specify the presence of stated elements, but do not preclude the presence or addition of one or more other elements. In the drawings, the size or thickness of elements may be exaggerated for clarity of explanation. It will be understood that when a layer of material is referred to as being "formed on" a substrate or another layer, it can be formed directly or indirectly on the substrate or another layer. That is, for example, an intermediate layer may be present. The material constituting each layer in the following embodiments is exemplary, and thus other materials may be used.

The terms "unit," "device," or ". machine," and "module," when used in this specification, refer to a unit in which at least one function or operation is performed, and may be implemented as hardware, software, or a combination of hardware and software.

The particular embodiments shown and described herein are illustrative examples of the present disclosure and are not intended to limit the scope of the present disclosure in any way. For the sake of brevity, conventional electronics, control systems, software development, and other functional aspects of the systems may not be described in detail. Furthermore, the connecting lines or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections, or logical connections may be present in a practical device.

The use of the terms "a" and "an" and "the" and similar referents should be construed to cover both the singular and the plural.

The operations making up the method may be performed in any suitable order unless otherwise indicated herein. The use of any and all exemplary language (e.g., "such as") provided herein is intended merely to illuminate in detail the technical spirit of the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed.

Fig. 1 is a view schematically showing a near-eye display device 10 according to an embodiment.

Near-eye display device 10 may be used as a standalone device (monocular) for one eye. Alternatively, the near-eye display device may be included in each of the two eyes. When the near-eye display device is coupled for the left and right eyes, the user may view a stereoscopic image. The near-eye display device may be used, for example, in augmented reality glasses, augmented reality helmets, virtual reality glasses, and the like.

Referring to fig. 1, a near-eye display device 10 may include a projection system 1, a first extension waveguide 2 on which light from the projection system 1 is incident, and a second waveguide 3.

Fig. 2 is a schematic plan view of a near-eye display device.

Referring to fig. 2, the first extension waveguide 2 may include a first surface 21 and a second surface 22 opposite to the first surface 21, wherein light from the projection system 1 is incident on the first surface 21. For example, the first surface 21 and the second surface 22 may be parallel to each other. However, the embodiments are not limited thereto.

The first expansion diffraction grating 2a may be included in the first expansion waveguide 2. For example, the first extended diffraction grating 2a may be disposed on the second surface 22. The first expanded diffraction grating 2a may be, for example, transmissive.

The second expanded diffraction grating 3a may be included in the second waveguide 3. The second waveguide 3 may include a third surface 31 on which light output by the first extension waveguide 2 is incident and a fourth surface 32 opposite to the third surface 31. The second expanded diffraction grating 3a may be disposed on the third surface 31. For example, the third surface 31 and the fourth surface 32 may be parallel to each other. However, the embodiments are not limited thereto.

The first extension waveguide 2 and the second waveguide 3 may be located on different planes. For example, the first extension waveguide 2 and the second waveguide 3 may be located on different planes within an angular range greater than 0 degree and equal to or less than 180 degrees. For example, the angle θ between the first surface 21 of the first extension waveguide 2 and the third surface 31 of the second waveguide 3 may have a range greater than 0 degree and equal to or less than 180 degrees. The 0 th order diffracted light output by the first extension diffraction grating 2a may be emitted from the first extension waveguide 2 at the same angle as the light incident on the first extension waveguide 2. Therefore, light incident on the first extension waveguide 2 can be widely extended by total internal reflection within the first extension waveguide 2, pass through the first extension waveguide 2 without refraction, and can be incident on the second waveguide 3. The first extension waveguide 2 and the second waveguide 3 may be transparent.

The same image may be used when the projection system 1 is used for each of the two eyes of the user. As another example, when using each projection system and a separate waveguide for each eye, the projection system may project each image for each eye. The projection system 1 may be located at a lateral side of the first extension waveguide 2.

For example, a near-eye display device for displaying augmented reality may be provided for each of the right and left eyes to configure glasses for displaying augmented reality.

Referring to fig. 2, the second diffraction grating 3a may have a structure in which an in-coupling diffraction grating 4 and an out-coupling diffraction grating 5 that receive light are arranged on one surface. Therefore, this case can reduce the manufacturing cost as compared with when the in-coupling diffraction grating and the out-coupling diffraction grating are arranged on different surfaces.

The near-eye display device includes an element for the right eye and an element for the left eye, and each element may include a projection system 1, a first expansion waveguide 2 including a first expansion diffraction grating 2a, and a second waveguide 3 including a second diffraction grating 3 a. The second waveguide 3 may include a light input region, an intermediate region that prevents output light from entering the eye, and a useful light output region that enables light to enter the pupil of the eye as the pupil moves while viewing the image. This will be described in detail later.

The display apparatus according to the embodiment can avoid the limitation of the field of view when the image is viewed vertically and horizontally. In other words, the visual field, eye movement, and reproduction efficiency can be increased, and the eyeglass system has a small size and thus is easily manufactured at low cost. These advantages are achieved by the fact that: that is, the in-coupling diffraction grating and the out-coupling diffraction grating are configured as a single diffraction grating, and light from the expansion diffraction grating for multiplexing or expanding light from the projection system is coupled to the diffraction grating for input/output to/from the waveguide. According to an embodiment, it is noted that a holographic diffraction grating may be used as the diffraction grating.

The following terms are used to explain the embodiments.

An Eyeball Movement Box (EMB) represents an inner region of the eye in which the eye can completely see the entire virtual image without loss while the eyeball is moving. The first expansion waveguide including the first expansion diffraction grating may be a system that multiplies the exit pupil. In other words, a plurality of exit pupils may be formed at the output of the first expansion waveguide instead of one exit pupil, and the first expansion diffraction grating and the first expansion waveguide may be disposed close to or in contact with each other, or may be spaced apart from each other by a certain distance. This formation of a multiplied exit pupil provides a wide eye movement area and thus allows the entire virtual image to be viewed completely without loss. Expansion or multiplexing of the beam refers to an increase in width (lateral dimension of the beam) that does not cause distortion (aberration).

The exit pupil (or pupil of the optical system) represents a paraxial image of the aperture stop in the image space formed by the optical system in the direct path of the light rays. This term is recognized in the optical arts. The main property of the exit pupil is that the entire image field is present at any point in time. The multiplication of the exit pupil may increase the size of the exit pupil without increasing the longitudinal dimension of the optical system.

The conventional optical system increases the size of the exit pupil and the longitudinal size of the conventional optical system increases, whereas the waveguide optical device according to the embodiment may increase the size of the exit pupil without increasing the longitudinal size due to multiple reflections of light rays within the waveguide. According to an embodiment, the expansion characteristic may occur when the grating lines of the waveguide and the diffraction grating are positioned at a certain angle with respect to the incident light. These will be discussed below. Diffraction efficiency is a property of a diffraction grating measured in units of percentage or fraction. The diffraction efficiency is the ratio of the energy contained in one of the diffraction orders to the energy incident on the diffraction grating. Diffraction efficiencies are well known.

According to an embodiment, the projection system 1 is tilted at an angle with respect to the first expansion diffraction grating 2a and the first expansion waveguide 2. When the first expansion diffraction grating 2a is applied to the first expansion waveguide 2, the grating lines of the first expansion diffraction grating 2a may be oriented such that some of the received diffraction orders of the incident light travel along the first expansion waveguide 2 with total internal reflection.

Light incident on the first expanded diffraction grating 2a propagates in three directions, but forms 0, -1 and +1 diffraction orders. Diffraction gratings can be created according to a number of methods. For example, the embossed diffraction grating may be formed by mask etching or nanoimprinting, and the holographic diffraction grating may be recorded as an interference pattern. For example, the theoretical angular range between the waveguides (between the first expansion waveguide and the second waveguide) and the theoretical angular range between the corresponding diffraction gratings (between the first expansion diffraction grating and the second diffraction grating) may be, for example, +90 degrees to-90 degrees. The grating period of the first expanded diffraction grating 2a may be, for example, in the range of 1200nm to 400nm with respect to visible colors. The grating period of the second diffraction grating 3a may range, for example, from 700nm to 200 nm.

Each of the first extension waveguide 2 and the second waveguide 3 may be configured with one of a diffractive optical element and a hologram element.

The proposed device can be manufactured using any suitable material, such as glass, polymer or crystal. In the present disclosure, the materials and parameters are not limited to those listed, as will be apparent to those skilled in the art. However, all options are not limiting of the present disclosure as these options will be apparent to those skilled in the art.

Fig. 2 is a view of a near-eye display device 100 according to another embodiment.

The near-eye display device 100 may include a projection system 101 that provides an image, a first extension waveguide 102 on which light from the projection system 101 is incident, and a second waveguide 103 on which light from the first extension waveguide 102 is incident.

The first expansion waveguide 102 may include a first surface 121 and a second surface 122 facing the first surface 121. Light from the projection system 101 may be incident on the first surface 121 of the first extension waveguide 102. The first extended diffraction grating 102a may be located on the first surface 121.

A reflective coating 104 may be formed on the second surface 122 of the first extension waveguide 102. The reflective coating 104 may improve the optical efficiency of the first extension waveguide 102. The present embodiment can improve optical efficiency as compared with the case where the first expanded diffraction grating 102a is located on the second surface 122. The reflective coating 104 may prevent light loss from occurring when the first extended diffraction grating 102a is positioned on the second surface 122.

The first expansion diffraction grating 102a may be included in the first expansion waveguide 102 such that a boundary between the first expansion diffraction grating 102a and the first expansion waveguide 102 has any one of various geometries, for example, a rectangle, a polygon, or an arbitrary geometry having an arcuate surface. In other words, the boundary surface where the first expansion diffraction grating 102a intersects with the first expansion waveguide 102 may have any one of various geometric shapes. Alternatively, the first expansion diffraction grating 102a may be directly formed on the surface of the first expansion waveguide 102 according to a method of forming a diffraction structure.

The first expanded diffraction grating 102a may be of a symmetric type or an asymmetric type. Another boundary contour may affect the performance of the image and the uniformity of the eye image. The boundary profile between the first expansion diffraction grating 102a and the first expansion waveguide 102 may be selected according to an objective lens, such as an objective lens that obtains a given picture of the image intensity distribution at different locations or compensates for uneven image brightness over the field of view from the projection system.

The second diffraction grating 103a may have a plurality of regions having different diffraction efficiencies. By combining with all elements of a device for displaying augmented reality, various configurations of diffraction efficiencies can compensate for uneven brightness in the field of view and improve the uniformity of the image seen by the eye.

Fig. 4 shows a plurality of regions according to the diffraction efficiency of the second waveguide 103.

Referring to fig. 4, the entire area of the second diffraction grating 103a may be divided into several areas. For example, the second diffraction grating 103a may comprise a first region I into which light is input, a second region II into which the output light does not enter the eye, and a useful third region III into which the output light enters the eye. When looking within the eye movement range, light from the useful third region III may enter the pupil of the eye when moving the pupil of the eye. For example, the first region I may comprise an in-coupling diffraction grating and the third region III may comprise an out-coupling diffraction grating.

As shown in fig. 4, the second diffraction grating 103a may have different diffraction efficiencies in the first region I, the second region II, and the third region III. The respective diffraction efficiency profiles of the first region I, the second region II, and the third region III of the second diffraction grating 103a are schematically shown in the graph.

The second diffraction grating 103a may provide diffraction efficiency in various forms.

For example, a) of fig. 4 will be described below.

Since the light emitted from the first extension waveguide 102 is incident on the second waveguide 103, the first region I of the second diffraction grating 103a to which the light is input may have the maximum diffraction efficiency. The first region I may have the lowest loss. The maximum diffraction efficiency of the second diffraction grating 103a can provide a user with high image brightness and wide brightness.

The second region II may have a minimum diffraction efficiency. In an ideal case, the diffraction efficiency of the second region II may be 0.

The third region III may have a relatively low diffraction efficiency in the useful light output field, thereby ensuring a uniform image output, i.e. a uniform image brightness. As a result, the relationship of the diffraction efficiency of the first region I > the diffraction efficiency of the third region III > the diffraction efficiency of the second region II can be established.

Next, b) of fig. 4 will be described.

Since the first region I is a region of the second diffraction grating 103a on which light is incident, the first region I may have the maximum diffraction efficiency, and thus light emitted from the first extension waveguide 102 may have the lowest loss and may be incident into the second diffraction grating 103 a. The maximum diffraction efficiency can provide high image brightness and thus a wide brightness setting for the user.

The second region II and the third region III may have an average diffraction efficiency less than the maximum diffraction efficiency. The average diffraction efficiency represents an average of the maximum efficiencies of the types of diffraction gratings used, and may refer to an intermediate value between the maximum efficiency and the minimum efficiency. Therefore, a relationship can be established in which the diffraction efficiency of the first region I > the diffraction efficiency of the second region II — the diffraction efficiency of the third region III.

Next, c) of fig. 4 will be described.

Since the first region I is a region of the second diffraction grating 103a on which light is incident, the first region I may have the maximum diffraction efficiency, and thus light emitted from the first extension waveguide 102 may have the lowest loss and may be incident into the second diffraction grating 103 a.

The second region II and the third region III may have gradient diffraction efficiency. The diffraction efficiency may have a profile gradually increasing from the second region II to the third region III. In this case, the overall optical efficiency of the near-eye display device may be increased compared to a) of fig. 4.

Next, d) of fig. 4 will be described.

The second region II may have a minimum diffraction efficiency.

The third region III may have a gradient diffraction efficiency.

In case of d) of fig. 4, the second waveguide 103 has good optical efficiency. In the case of b) of fig. 4, it is easy to manufacture the second diffraction grating.

Fig. 5 is a perspective view of a near-eye display device 200 according to another embodiment.

Near-eye display device 200 may include a projection system 201, a first expansion waveguide 202, and a second waveguide 203. The first expansion diffraction grating 202a may be included in the first expansion waveguide 202. The first expansion waveguide 202 may include a first surface 221 and a second surface 222 facing the first surface 221. For example, the first expanded diffraction grating 202a may be disposed on the second surface 222. The second expanded diffraction grating 203a may be included in the second waveguide 203. Light from the projection system 201 may be incident toward the second surface 222 of the first extension waveguide 202.

The second waveguide 203 may comprise a first region I into which light is input, a second region II where the output light does not enter the eye, and a useful third region III where the output light enters the eye. When looking within the eye movement range, light from the useful third region III may enter the pupil of the eye when moving the pupil of the eye.

No diffraction may occur in the second region II of the second waveguide 203. In other words, the diffraction efficiency of the second region II may be 0.

For example, the second region II of the second waveguide 203 may not include the second diffraction grating 203a, or may have zero diffraction efficiency. The second region II may not have any functional load for outputting light. Light may not be emitted from the second waveguide 203 through the second region II of the second waveguide 203 and may propagate farther along the second waveguide 203 due to total internal reflection. Therefore, light loss can be reduced.

Fig. 6 is a view of a near-eye display device 300 according to another embodiment.

Near-eye display device 300 may include a projection system 301, a first expansion waveguide 302, and a second waveguide 303. According to the present embodiment, the first extension waveguide 302 and the second waveguide 303 may be integrally formed with each other. A first expansion diffraction grating 302a may be included in the first expansion waveguide 302. The first extension waveguide 302 may include a first surface 321 and a second surface 322 facing the first surface 321. For example, the first expanded diffraction grating 302a may be disposed on the second surface 321. However, the embodiment is not limited thereto, and the first extended diffraction grating may be disposed on the second surface 322. A second expanded diffraction grating 303a may be included in the second waveguide 303. Light from the projection system 301 may be incident on the first surface 321 of the first extension waveguide 302.

The first extension waveguide 302 and the second waveguide 303 may be configured with a single piece of bent waveguide. The first extension waveguide 302 may constitute a portion of the waveguide that is bent in one direction, and the second waveguide 303 may constitute a portion of the same waveguide that is bent in another direction. The present embodiments facilitate the manufacture of near-eye display device based eyewear. The operating principle of the present embodiment is the same as the description given above.

Fig. 7 is a view of a display apparatus 400 according to another embodiment.

The display device 400 may include a projection system 401, a first extension waveguide 402, and a second waveguide 403. The first extension waveguide 402 may include a first surface 421 and a second surface 422 facing the first surface 421. The first surface 421 and the second surface 422 may be parallel to each other. The first expansion diffraction grating 402a may be disposed on a first surface 421 of the first expansion waveguide 402. The reflective coating 404 may be disposed on the second surface 422.

A second expanded diffraction grating 403a may be included in the second waveguide 403. Light from the projection system 401 may be incident on the first expansion diffraction grating 402a of the first expansion waveguide 402. The second waveguide 403 may include a third surface 431 and a fourth surface 432 facing the third surface 431. The third surface 431 and the fourth surface 432 may be parallel to each other. The second expanded diffraction grating 403a may be disposed on the fourth surface 432. The light output by the first extension waveguide 402 may be incident on the fourth surface 432.

The first extension waveguide 402 and the second waveguide 403 may be arranged, for example, in parallel with each other. A portion of the first surface 421 of the first extension waveguide 402 may be arranged to face a portion of the fourth surface 432 of the second waveguide 403 by overlapping the portion of the fourth surface 432 of the second waveguide 403. The first extension waveguide 402 and the second waveguide 403 may be arranged to be separated from each other. For example, the second waveguide 403 may be positioned above the first extension waveguide 402. The embodiment can be well applied to an augmented reality helmet mounting system.

The near-eye display device according to the embodiment may be applied to, for example, augmented reality glasses.

The augmented reality glasses may include a first element for a left eye and a second element for a right eye.

Referring to fig. 8a, augmented reality glasses may include a first element for generating and transmitting an image for a left eye and a second element for generating and transmitting an image for a right eye.

Referring to fig. 1, each of the first and second elements may include a projection system 1 and a first expansion waveguide 2 having a first expansion diffraction grating 2 a. The second waveguide 3 and the second diffraction grating 3a of the first element for the left eye may be disposed on the left frame LGF disposed on the left eye. The second waveguide 3 and the second diffraction grating 3a for the right eye may be arranged on the right mirror frame RGF arranged on the right eye. According to the present embodiment, different images can be provided to the left and right eyes, and thus a stereoscopic image can be provided.

In the augmented reality glasses of fig. 8b, a first element (for the left eye) may be coupled to a second element (for the right eye). For example, the second waveguide 3 of the first element (for the left eye) may be used together in the second element (for the right eye). For each of the left and right eyes, a projection system 1 and a first extension waveguide 2 may be included. The second waveguide 3 having the second diffraction grating 3a for input/output common to the left and right eyes may be disposed on a common frame GF located on the left and right eyes. The second waveguide 3 may combine the respective fields of view of the left and right eyes with each other.

Each of the first and second elements includes a projection system 1 and a first expansion waveguide 2 having a first expansion diffraction grating 2a, and the first and second elements are located on lateral sides of the left and right eyes, respectively. In this embodiment, the two projection systems 1 have a single common driver for synchronizing their operation, but may not provide stereoscopic images.

Fig. 8c shows another example of augmented reality glasses.

According to this embodiment, the first element (for the left eye) may be coupled to the second element (for the right eye). In other words, the first element may be used for both the left and right eyes. The second waveguide 3 including the second diffraction grating 3a may be disposed on a common lens frame GF located on the left and right eyes. According to the present embodiment, the first element (for the left eye) and the second element (for the right eye) may include a single projection system 1 and a single first expansion waveguide 2, and the projection system 1 and the first expansion waveguide 2 may be disposed on lateral sides of the left eye or the right eye.

Fig. 9 and 10 are views for explaining an operation method of the near-eye display device according to the embodiment. An operation method of the near-eye display device according to the embodiment will be described with reference to the embodiment of fig. 3.

According to an embodiment, the +1 st order light, the 0 th order light, and the-1 st order light may be used. Referring to fig. 9, the first extended diffraction grating 102a and the first diffraction grating 103a may be located on different planes, and light may be output at the same angle as an input angle of the light. Therefore, the image seen by the eyes is not limited by the coordinate axis. The image is bright, the eye movement area is enlarged, and the image is more convenient for the user. For example, a small projector such as a DMD projector, an LCoS projector, an SLM projector, or a laser scanning projector may be used as the projection system 101.

Fig. 9 and 10 show how light is expanded in the first expansion waveguide 102 when the first expansion diffraction grating 102a is disposed on the first surface 121 of the first expansion waveguide 102.

As shown in fig. 9 and 10, the first expansion waveguide 102 including the first expansion diffraction grating 102a may be disposed on a region of an exit pupil of the projection system 101. The first extension waveguide 102 may be fabricated from any suitable material, such as glass, plastic, or a crystalline material, using typical methods.

Referring to fig. 11, it should be noted that it is important how the grating lines 110 of the first extended diffraction grating 102a are positioned with respect to the incident light. Fig. 11 is a view showing the relative arrangement of the grating lines 110 of the first extended diffraction grating 102a with respect to incident light. The first expanded diffraction grating 102a may diffract incident light into-1 order light, 0 order light, and +1 order light. In this case, all diffraction orders are useful. A condition required for expanding (multiplying) the light from the projection system 101 is a layout position of the grating lines 110 of the first expansion diffraction grating 102a arranged in the propagation direction of the field center of the projection system 101.

Concepts such as angular fields and linear fields are known to those of ordinary skill in the art. In the present application, however, the angular field is related to the terms field center and field edge. In other words, the grating lines 110 of the first extended diffraction grating 102a may be positioned according to the projection of the incident light on the first extended diffraction grating 102 a. The acute angle alpha between the projection of the main beam of the projection system 101 onto the plane of the first extension waveguide 102 and the grating line 110 may be in the range of-30 degrees to +30 degrees.

As shown in fig. 9 and 10, a light beam from the projection system 101 may be incident on the first expanded diffraction grating 102a, and as a result of diffraction, the light beam may be divided into several light rays (diffraction orders) expanded at a certain angle with respect to an incident angle. The 0 th order diffracted light can be obtained from these several light rays, and these light rays can not only not change the direction of expansion of-1 st order diffraction with respect to the incident light but also change the direction of expansion of +1 st order diffraction with respect to the incident light.

The-1 st order diffracted light and the +1 st order diffracted light may be spread at symmetrical angles with respect to the incident light. The 0 th order diffracted light 106 may pass through the first extension waveguide 102 and may be at an incident angle θ to incident light₁The same exit angle theta₂Is emitted from the first extension waveguide 102, and may be incident on the second diffraction grating 103a of the second waveguide 103. Incident angle theta₁And an exit angle theta₂Is based on the normal of the first expanded diffraction grating 102 a.

The-1 st order diffracted light and the +1 st order diffracted light remain in the first extension waveguide 102, propagate from the first extension waveguide 102, are reflected by the second surface 122 (i.e., the surface opposite the first extension diffraction grating 102 a), and are fed back to the first extension diffraction grating 102a via total internal reflection. Each of the-1 st order diffracted light and the +1 st order diffracted light undergoes diffraction, and as a result, 0 th order light, -1 st order light, and +1 st order light are formed again, thereby forming the first extension region 111. The 0 th order diffracted light is emitted from the first extension waveguide 102 and enters the second diffraction grating 103a of the second waveguide 103. As described above, each of the-1 order light and the +1 order light may be expanded in the first expansion waveguide 102 to form the second expansion region 112. Each diffracted light can be diffracted again to a new 0 th order, a new-1 st order, and a new +1 st order. Although only the first extension region and the second extension region are shown in the drawings, more extension regions may be formed. As a result, as shown in fig. 9, the exit pupil may be multiplied by the first expansion region 111 and the second expansion region 112 with respect to the light entering the first expansion waveguide 102.

After the 0 th order diffraction light from the first extension waveguide 102 is incident on the second waveguide 103, the 0 th order diffraction light is incident on the second diffraction grating 103a in the second waveguide 103 and thus travels toward the eye, and the 0 th order light, -1 st order light, and +1 st order diffraction light are formed again. The-1 st order diffracted light is extended out of the eye and may therefore become useless. The 0 th order diffracted light may pass through the second waveguide 103 and may be emitted from the second waveguide 103 in the same direction as the initial beam from the projection system 101. Only the +1 st order diffracted light expanded at the angle of the 0 th order diffracted light may experience the CIR in the second waveguide 103 and may remain in the second waveguide 103. The +1 st order diffracted light enters the second diffraction grating 103a again from the inside of the second waveguide 103 and is divided into 0 order, +1 order, and-1 order again, and new 0 th order diffracted light is emitted from the second waveguide 103 and enters the eye. Then, when the new +1 st order diffracted light is further expanded along the second waveguide 103, the above process may be repeated, and each 0 th order diffracted light may enter the eye as described above.

Due to the above-described light expansion, there are a plurality of exit pupils (see 111 and 112 of fig. 9) and these exit pupils are spaced apart from each other, and thus a field in which the eye can move, that is, a field in which no image appears from the field of view of the eye can be widely formed. Therefore, the eyeball-movement region can be widely formed. Since the near-eye display device according to the embodiment expands light and uses all diffraction orders, the near-eye display device according to the embodiment can reduce loss of light from the projection system 101.

When the first expansion diffraction grating 102a is positioned on the first surface 121 of the first expansion waveguide 102 on which light from the projection system 101 is incident, the light from the projection system 101 may be incident on the first expansion diffraction grating 102a and may be diffracted into +1 order light, 0 order light, and-1 order light. The 0 th order diffracted light is output from the first extension waveguide 102 and enters the second diffraction grating 103 a.

When the second surface 122 of the first expansion waveguide 102 includes the reflective coating 104 and the first expansion diffraction grating 102a is located on the first surface 121 of the first expansion waveguide 102, both the-1 st order diffraction and the 0 th order diffraction are reflected by the reflective coating 104 and emitted through the first surface 121 of the first expansion waveguide 102.

When the first expansion diffraction grating 102a is located on the second surface 122, light from the projection system 101 enters the first expansion waveguide 102, is diffracted into +1 order, 0 order, and-1 order while passing through the first

expansion diffraction grating

102a, and 0 order diffracted light is output from the second surface 122 of the first expansion waveguide 102 and enters the second diffraction grating 103 a.

As described above, in order to effectively multiply light, light from the projection system 101 may be incident on the first expansion waveguide 102, and an angle of entering the first expansion diffraction grating 102a may be in a range of 0 to 90 degrees with respect to a normal line of the first surface 121 of the first expansion waveguide 102. Light from the projection system 101 is incident between the first surface 121 of the first extension waveguide 102 and the normal to the first surface 121. As described above, the acute angle between the projection of the main beam of the projection system 101 on the first surface 121 of the first extension waveguide 102 and the grating line 110 may be in the range of ± 30 degrees.

According to an embodiment, the second diffraction grating 103a formed on the second waveguide 103 may be used to receive incident light from the first extension waveguide 102 and output the light to the eye region. Due to the position of the first extension waveguide 102 including the first extension diffraction grating 102a, the direction of the same grating lines of the second diffraction grating 103a can be used for inputting light to the second waveguide 103 and outputting light from the second waveguide 103 to the eye region. This is because the first expansion waveguide 102 including the first expansion diffraction grating 102a is located on a plane different from that of the second waveguide 103 including the second diffraction grating 103 a.

For clarity, advantages according to various embodiments will now be described by comparison with the comparative examples of fig. 12 and 13.

Fig. 12 illustrates elements of a typical augmented reality device according to a comparative example.

The exemplary augmented reality device of fig. 12 includes a projection system 1101, a waveguide 1102, and a diffraction grating 1103 included in the waveguide 1102. Radiation from the projection system 1101 enters the waveguide 1102 through a narrow radiation region (a). After the light passes through the diffraction grating 1103, only one diffraction order enters the waveguide 1102, and there is no intersection of different regions of the field of view in the region where the light enters the eye. The lower portion of the field of view expands obliquely to region (b) along waveguide 1102 and no light enters the pupil of the eye when the eye looks at the center or top of the field of view. Since the output light comes out from the central part of the field of view only through the narrow region (c), when the eye sees the central part of the field of view, as a result, only a narrow band of the image is seen.

However, as shown in fig. 13, when the first expansion waveguide 2 is used according to the embodiment, light expanded by the first expansion waveguide 2 is input to the expansion region (a) in the second waveguide 3, and the expanded light enters the pupil of the eye while intersecting the region (B) and the region (C). A wide field of view of eye movement can be provided while maintaining a lower portion of the image and an upper portion of the image.

In the solutions known in the conventional art, when the width of the field of view is limited, the edges of the image are sharp because the total internal reflection is disturbed, but the light used as the edges of the image does not enter the field of view where the eye moves and therefore cannot be seen. However, a near-eye display device according to various embodiments may enable a user to see the entire image with a wide field of view.

Due to its wide field of view, the claimed disclosure may provide a user with a wide field of view of eye movement and may provide an interesting presence in, for example, a game or movie. High resolution can provide true presence. The user can see almost all the same details as the real world. A user may watch a movie using glasses containing a device that displays augmented reality and may immerse himself completely in the virtual world.

The near-eye display device according to the embodiment may be used in AR/VR, HUD, and HMD devices that need to have a high resolution image and a wide field of view. Augmented reality glasses using the proposed device to display augmented reality in bright ambient lighting including daylight may provide bright and clear images.

While the disclosure has been described in connection with certain embodiments, it should be understood that the disclosure is not limited to those specific embodiments. On the contrary, the present disclosure is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the claims. Further, the disclosure retains all equivalents of the claimed disclosure even when the claims are changed.

Claims

1. A near-eye display device comprising:

a projection system configured to display an image;

a first expansion waveguide comprising a first surface and a second surface opposite the first surface, wherein light from the projection system is incident on the first surface or the second surface;

a first expansion diffraction grating included in the first expansion waveguide;

a second waveguide on which light emitted from the first extension waveguide is incident; and

a second diffraction grating included in the second waveguide,

wherein the first expansion diffraction grating and the second diffraction grating are located on different planes such that 0 th order diffraction light emitted from the first expansion waveguide is incident on the second waveguide.

2. The near-eye display device of claim 1, wherein light from the projection system is incident on the first expansion waveguide, and an angle at which the light is incident on the first expansion diffraction grating has a range of 0 to 90 degrees relative to a normal to a surface of the first expansion waveguide.

3. The near-eye display device of claim 1, wherein grating lines of the first extended diffraction grating are arranged along a projection of light from the projection system onto the first extended diffraction grating.

4. The near-eye display device of claim 1, wherein an acute angle between a projection of a main beam of the projection system on the plane of the first expansion waveguide and a grating line of the first expansion diffraction grating has a range of +30 degrees to-30 degrees.

5. The near-eye display device of claim 1, wherein the first expansion diffraction grating is located on the first surface of the first expansion waveguide on which light from the projection system is incident.

6. The near-eye display device of claim 5, wherein the second surface of the first expansion waveguide has a specular coating.

7. The near-eye display device of claim 1, wherein the second waveguide comprises a first region on which light is incident, a second region where light does not enter the user's eye, and a third region where light enters the pupil of the eye.

8. The near-eye display device of claim 7, wherein the near-eye display device is configured such that diffraction does not occur in the second region of the second waveguide.

9. The near-eye display device of claim 7, wherein the second diffraction grating is configured to have the following relationship: the diffraction efficiency of the first region > the diffraction efficiency of the third region > the diffraction efficiency of the second region.

10. The near-eye display device of claim 7, wherein the second diffraction grating is configured to have the following relationship: the diffraction efficiency of the first region > the diffraction efficiency of the second region, i.e., the diffraction efficiency of the third region.

11. The near-eye display device of claim 7, wherein the first region of the second diffraction grating has a high diffraction efficiency, and the second and third regions have a gradient diffraction efficiency.

12. The near-eye display device of claim 1, wherein the first expansion waveguide and the second waveguide comprise a monolithic, curved shaped waveguide.

13. An augmented reality eyeglass comprising:

an element for the left eye and an element for the right eye,

wherein at least one of the element for the left eye and the element for the right eye comprises: a projection system; a first expansion waveguide comprising a first surface and a second surface opposite the first surface, wherein light from the projection system is incident on the first surface; a first expansion diffraction grating included in the first expansion waveguide; a second waveguide on which light emitted from the first extension waveguide is incident; and a second diffraction grating included in the second waveguide, an

The first expansion diffraction grating and the second diffraction grating are located on different planes such that the 0 th order diffraction light output by the first expansion waveguide is incident on the second waveguide.

14. A method of operation of a near-eye display device, the method of operation comprising:

causing light from the projection system to be incident on the first extended diffraction grating;

forming-1, 0 and +1 order diffractions from respective diffractions of the light beam incident on the first expanded diffraction grating;

outputting 0 th order diffracted light from the first extension waveguide, and inputting the 0 th order diffracted light to the second waveguide;

expanding-1 st order and +1 st order diffracted lights in the first expansion waveguide due to total internal reflection and feeding back the expanded-1 st order and expanded +1 st order diffracted lights to the first expansion diffraction grating, and causing the expanded-1 st order and expanded +1 st order diffracted lights to be incident on different positions on the first expansion diffraction grating; and

a new-1 order diffraction, a new 0 order diffraction, and a new +1 order diffraction are formed from each of the-1 order diffracted light and the +1 order diffracted light.

15. The method of operation of claim 14, wherein each 0 th order diffracted light incident on the second waveguide passes through a second diffraction grating via the second waveguide, the diffraction of each light ray incident on the second diffraction grating forms-1 st order diffraction, 0 th order diffraction, and +1 st order diffraction, and the +1 st order diffraction is reflected by a surface of the second waveguide opposite an eye-facing surface of the second waveguide and is again incident on the second diffraction grating.